So I decide not to consider branches with less than 1000 observations, a 1% of
the original number of observations. Therefore, according to the rpart.control
help pages, I set minbucket=1000. However,

> arbol.bsvg.02

n= 100000

node), split, n, loss, yval, (yprob)

denotes terminal node

root 100000 6657 0 (0.9334300 0.0665700) *

And I get an "empty" tree. But there were branches in the original tree with
more than 1000 observations. Something similar happens if I set minsplit (or
both minbucket and minsplit) to a similar value: I end up with the same root,
branch-less tree.

Am I misreading something? Can anybody cast a light on the correct usage of the
minbucket (and/or minsplit) for me?